Art of producing low boiling point hydrocarbon oils from high boiling point hydrocarbon oils



1 9 w 1 5 WSM 1 h s 4 ly 18, 1933- H. R. sNow El AL ART OF PRODUCING LOWBOILING POINT HYDROCARBON OIL FROM HIGH BOILING POINT HYDROCARBON OILSFiled Feb. 10, 1950 Q Eden July 18, 1933. R s w ET AL 918,991

H. ART OF PRODUCING LOW BOILING POINT HYDROCARBON OI FROM HIGH BOILINGPOINT HYDROCARBON OILS Filed Feb. 10, 1930 4 Sheets-Sheet 2 520525075.fire Zd 0572020, fledertbhifuZZzvargcfi;

H. R. SNOW Er AL G LOW 1,918,991 HYDROCARBON OILS G POINT HYDROCARBONOILS ART OF PRODUCIN BOILING POINT FROM HIGH BOILIN July 18, 1933.

Filed Feb. 10, 1930 4 Sheets-Sheet 3 1. U1 \H. 1. a(IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII'I vane? July 18, 1933.

H. R. SNOW ET AL 1,918,991 ART OF PRODUCING LOW BOILING POINTHYDROCARBON OILS FROM HIGH BOILING POINT HYDROCARBON OILS Filed Feb. 10,1930 4 Sheets-Sheet 4 fiZ/GR 9775. EroZcZfOSrzow 35 zzz'va a 3 these Adifficulties.

present inventlon, a gasoline or motor fuel product of the desiredantl-knock character- Patented Jilly 18, 1933 UNITED, STATES PATENTOFFICE- HAROLD R. SNOW AND FREDERICK SULLIVAN, .13., OF HAMMOND,INDIANA, AS-

SIGNORS TO STANDARD OIL COMPANY, OF WHITIN G, INDIANA, A CORPORATION OFINDIANA ART OF PRODUCING LOW BOILING POINT HYDROCARBON OILS HIGH BOILINGPOINT H-YDROCARBON OILS i Application filed February 10, 1930. SerialNo. 427,216.

The present invention relates to improvements in the manufacture ofgasoline or motor fuel from heavier hydrocarbon oils by cracking ordecomposition in the vapor phase, more particularly for the productionof motor fuel products in the gasolineboiling point range havinganti-knock properties equivalent to those secured by the addition oftetraethyl lead to virgin Mid-Continent gasoline in proportions of atleast 1.5 cc. and preferably 2 cc. or-higher per gallon.

In vapor phase operations as hitherto conducted, the production of amotor fuel product of suitable anti-knock characteristics has beenattended with various difficulties, such as low gasoline yields ascompared with ordinary liquid phase cracking operations, excessive gaslosses, coking troubles and the like, as a result of which variousexpedients in operation have been introduced, for example, theintroduction of inert gases, in the system as heat carriers, theuse ofcatalysts and of fillers for the heating tubes or members, and the likein the effort to obviate In accordance with the istics may be securedwith yields commensurate with those obtainable in liquid phase crackingprocesses, with relatively low gas and tar losses, and without suchspecific operating means'as' the introduction of gases,

'the use of special cores in the heating elements or the use ofcatalysts. Y The invention will be fully understood from the. followingdescription illustrated by the accompanying drawings, in which:

Figure 1 is a diagrammatic view ofapparatus suitable for carrying theinvention into effect;

Fig. 2 is a diagrammatic view of a modified form of apparatus suitablefor carrying out the invention;

Fig. 3' is a sectional diagrammatic view of the enlarged reactionchamber of Fig. 2;

Fig. 4 is a sectional diagrammatic view of the fractionating column ofFig. 2; and

Fig. 5' is a chart indicating suitable temperature gradients in theheating operation in carrying out the invention.

- shaft 7, providing initial heating and vaporizing sections and 10 inwhich little cracking occurs, and a section 11 in which the restost ofthe cracking of the vaporizing and m takes place. The oil supplied tothe heating coil enters the coil through the pipe 12, passes through theinitial heating, section 10 and then through the pipe 13 to section 10and through the cracking section 11. The oil is subjected to rapidheating 11 section 10, which in the form .of furnace illustrated, issubjected to radiant heat. From the cracking section 11 the vapors passthrough line 14 provided with pressure release valve and arrangedso-that they discharge tangentially into the separator tower 16 belowthe liquid level. .A body of condensed liquid or tar is retained in thelower portion 17' of the separator tower 16, and in order to effectivelycool the entering products from the coil, some of this tar may be drawnthrough the line 32* and be circulated by. pump through a cooler 32 andreturned through line 32". The cooled tar rapidly cools the entering hotvapors.

The separator tower 16 may be provided above the opening of the line 14thereinto with suitable baflie or fractionating plates 18. At anintermediate point in the flash tower, a draw-off plate is provided,this plate being diagrammatically illustrated as this condensate may bepermitted to overflow and return to the liquid 17. Above the draw-offplate 20 additional fractlonating plates 22 are provided, and in the topof the Fresh oil to-be fed to the system may suit-.

ably-be supplied" through the line 24 to the heat exchangecoilsfl inthetop of the-sep- Can arator tower- 16', thereby controlling theterivperature of the vaporsissuing from the tower, and may then'rpass throughthe valved line 25 to line 26," by which the oil' is con.- ducted to adistributor 27- inth lower por; tion of the separator tower: belowthed-rawofi' plate 20. If desired,additional'oil to be fed'into'theysys'tem may be supplied to the line 26' through the valved; line 28or excess feed u-sed for cooling at the top of the-tower may be drawnoff, through the same valved line 28; As will be more fully pointed outhereinafter, the portions of the feed" stock which are-to be supplied'tothe heating coils are completely Qvaporizedin-thelower portion of theseparator tower,'the vapors pass upwardly through-the vapor.co'nduitj21- in the draw-off plate 20 The desired constituent-s of thestock,.' together';withreflux condensate from heating coil, arecollected on the draw-off plate 20, withdrawn-by the hot oil pump 29 andcharged by the lattento the line 12 entering the heating (coil. v

Vapors uncondensed in the tower :16 pass out through the vapor line 30'to a suitable condenser 31 or, if desired. to a traction-a1 condenser.-The heavy liquid or tarcolle'cted in the lower portion 1 Z o f'theseparator tower 16,- may be withdrawn as desired through the valved line32, 'and passed coolers or heatexchangers desired;

In carrying .out the invention, the oil or composite feed which .iscompletely vaporizab-le' and is delivered to the heating coil throughthe line 12-is heatedto effect its rapid vaporization and subsequenthigh temperature crackingof the vapors to as great" an extent aspossible. .In order to secure-the rethrough suitable (not shown) assultswhich we desire to obtain, the oilfis.

heated with a coil outlet pressure of from to iOO'lbs.,-to an outlettemperature of from 850jto 975 F., typical operating: conditions being apressure of about-,l'z5' to lbs. and a temperature of about 925 F.-

In the heating operatiomithe oil isbro'ught from a temperature belowthat-at which active cracking takes place, andat which vaporizationbegins ,-toa high'cracking tem: perature approximating the desiredvoutlet temperature. at a rapid rate.- so that cracked products in thegasoline boiling point range which are-formedbefore the oil reaches atemperature of 850 F..'bear a low ratio to the-total quantity of such'productsformed vin the operation, say, less than 15% of the gasoline..The proportion of liquid phase cracking is thus miniinizedsince morethan 85% of the gasoline produced in the opera;

the vapors issuing from the tion is produced at temperatures within therange of from about 850 F. to about 97 5 F. A suitable routing. of theoil is'illustrated diagrammatically in connection with" the fur-- nape 5in Fig. 1. Siich'a; furnace may have for example, 18 horizontal rowsoftubes of 16 tubes'each. The composite top row, passesdownw'ardlythrough the tubes of teach-successive row for 'five rows,

and is then carriedby the piped? to the 'low-,

ermost .and hottest row andrises successively through the horizontal.row's, making-its exit through Tthe line '14; at-the thirteenth row Ifrom the bottom. In such {an operation,

with-suitable control ofthe amount of crackn i p e 13 may be between 525and 650 ;F.,.which is below the temperature at which appreciablecracking occurs? It then-passes to the-"bottom row of tubes in thefurnace in which there-is the-greatest heat-input, and is rapidly raisedtoa; temperature. above 850 F., as w well as convection 'heat or. byother rapid heating nie,ans. It is .subst-aht-ially .com-

pletely vaporized and brought to 'a high crackingtemperature "in'ithebottom two rows of tubes; In its continued travel through ning elevenrows of itubes, it may the remal be gradually raised-in temperature, b g

broughtIto-an outlet temperature approxima'ting .925 F.

I illustrates a typical operation of; this character. -:In thechart'thereillustrated, the'coordinates represent respeotivelythetemperature'of the oil andthe tuberowso'f the" heatinglfurnace, It willbe noted that in the first five rows of traveltl'ie'oil is brought to a.

where cracking becomes appreciable to .a F. very rapidly temperature "ofabout. 850- feed enters the s the temperature of the oil after. passingthrough the {top five'rows'and'enter- "ing the tub by. exposure 'toradiant heat as" the 'solid line curve designated I travel" itisgradually' rought;

so that no crack ed products or but a low pro 7 portion thereof areformed before'ithe oil reaches 850 F.

'In carrying out the dependable-measure ofthe time to which the feedto'the-coil, since the amount of cracking to gasoline effected the oilis exposed to cracking temperature in the coil. the outlet temperatureand approximate temperature gradient while'undcr crack operation withthe a ng conditionscontrolled as hereiubefore set forth, we havefoundthat the most" is a measure of the'tilue' ing conditions beingknown. The amount of cracking to gasoline per pass which is secured isreadily within the control ofthe operator, since it may be variedbyvarying the rate of feed under given temperature and pressureconditions. The cracking per pass may be decreased by increasing therate of feed and vice-versa. The minimum desired cracking to gasolineper pass ranges from 2.5% at 100 lbs. .pressure to 13% at 250 lbs.

outlet pressure, at outlet temperatures of 850.

to 975 F. for a product having a 1.5 cc. tetraethyl lead equivalent. Forhigher lead equivalent a higher cracking to gasoline per pass isnecessary; thus for a 2.0 cc. product, the minimum' ranges from 4%gasoline per pass at 100 lbs. to about 16.5% per pass at 400 lbs.

In Fig. 2 there is illustrated a modified form of apparatus for carryingout the present invention, in which the vapor products from the heatingcoil are discharged into a reaction chamber, in which the vapors aremaintained at cracking temperature for a substantial further period oftime and the capacity of the system increased.

Referring to Fig. 2 of the drawings, the numeral 40 designates a heatingfurnace containing heating coils 41, so constructed that the conditionsof operation are similar tothose described in connection with theheating coil of the form illustrated in Fig.1. The feed to the coilenters through the line 42, first passing through an initial heatingsection 43 in whichit is heated to a temperature below that at whichvaporization and cracking begins. From this initial heating section 43,the oil passes through the line 44 to the'lowermost row of tubes of thevaporizing and: cracking section 45 inwhich it is rapidly vaporized andbrought to-the desired cracking temperature.- The heated oil vapors passout through the pipe46 and are discharged into the lower portion of thereaction chamber 47 through an inlet device 48 above the level of anytar or liquid contained in the latter.

In the operation of the soaking drum, conditions are so maintained thatthe chamber is largely filled with vapor and so that there is a. minimumof turbulence in the vapor in thechamber and a; maximum temperaturegradient between the vapor inlet and the vapor outlet. It has been foundthat these conditions can be most readily secured in an elongatedvertical chamber. Although, it might appear that turbulence of thevapors in the drum could be most readily avoided by introducing vaporsnear the top of the chamber and removing them near the bottoln, byreason of the-increasing density of the vapors as they decrease intemperature, it has been found that such operation is notconducive toamaxlmum temperature'gradlent and a minimum of turbulence, but leads tomixing and to even temperatures throughout the drum orchamber. It hasbeen found-advisable to' introduce the heated Vapors from the heatingcoil in the lower portion of the reactionchamber, removing vapors fromthe chamber at the top, because decreasing density due to cracking morethan offsets increasing density due to cooling.

The distributing device 48 by which the vapors are introduced in thechamber is of a form providing arapidly expanding discharge opening andis conducive to the introduction of the vapors at a low velocity toavoid excessive turbulence. In the formv illustrated diagrammatically inFig. 3. it consists of an expanding opening 49- below which is provideda baffle plate 50. The details of this inlet construction form thesubject matter of the co-pendjng application of Snow, Serial No.447,265, filed April 25, 1930.

The reaction chamber is suitably insulated to maintain the desiredreaction temperature moved through the outlet line 51 and the formationof coke dep asits in this line is prevented by any suitable means, forexample. by\the injection thereinto of fresh feed by meansof the line 52and 'nozzle 53. A suitable device for this purpose is shown more indetail in the co-pending application of Snow, Serial N o. 428,431, filedFebruary 14. 1930. The stock thus introduced passes off with the vaporsfrom the reaction chamber' through the line 51.

By thus introducing the heated products from the heating coil into thelower portion of vertical reaction chamber without substantialturbulence and removing the vapors from the top, secure a slow andprogressive movement of the vapors through the reaction chamber. with ahigh temperature gradient indicating the lack of turbulence therein. Thedifference in temperature between the vapors in proximity to the inletand those in proximity to the outlet should be at least 10 to 15 and ina reaction chamber, for example, six feet in diameter and forty feethigh, it has been found possible to secure a temperature gradient of 30and higher in the vapor. The tar, if any is present, is removed from thereaction chamber through an outlet 54, which projects upwardly a shortdistance into the reaction chamber from its lowermost portion and limitsthe level of tar; In order to prevent coke formation at this outlet. andavoidconsequent stoppageof flow of heavy liquid or tar, the outlet issurrounded by a 'coil 55, to which a sultable coolit. has been foundpossible to *to be fractionatedtherein.

:- ale 53 directed towards the yaporoutletin thereaction chamber."

, Thevaporspass out of the reaction chain-1 her through the line 51" andpressure release valve 61 into the lower portion-ofthe fractionatingcolumn 6O, being joined before entering the latter liquid products or:tar

withdrawn from -,-the reaction chamber through line 54 and pressurerelease valve 62. At an intermediate pointin the fractionatingcolumn 60there is provided asuitable refluxfd-ra'w-off plate 63' as shown in'Figi4, pr ovided with a. vapor conduit'64, so that vapors from the l'werportion of the column, may ascend into the upper portion A pluralityof fractionatin'g plates of any suitable type, 65, are provided in thecolumn abovejthe point of admission of thevapors and liquid from the-reactionchamberf.- Above the draw-01f plate inthe ,col'umri '63 thereare likewise provided a pl'uralityof-suitable fractionating plates 36,and in order to securepadd-itional cooling action in the fractionatingcolumn, suitable heat eXchan'gecoi-ls 67 and 68 are provided therein,the former being near the vapor outlet of the column,'and the latteratan intermediate point therein. A suitable cooling medium,--such as' thefresh feed to. be supplied to-the system, may enter T. coil 67th'roughthe line 59. After passing through the coil,"itlea'ves'.the-latterth'roughline 70 and enters the coil 68", out of which itpassesithrough the l=ine'71,-and the line 8 to'th'e coilsurroundin g'theliquid .outlet 54 fromthe reaction chamber 47 as .hereinbeforedescribed.-

, Refluu c-(mdensate formed from the vapors which -"en.'te'r thefract'iona'ting column and which are derived from the vapor'product's ot reactionand the vaporized fresh feed introduced into the reactionchamber 47, are withdrawn fromjthe-draw,-ofi' plate 63 in the column ()0through the line 72 and discharged into'the the stripping-tower 73 ashereinafter .further described. Liquid products separated 'in' the-lowerportion ofthe column (30 'co'lect therein and inav 'be Withdrawn throughthe valvedline =74 Uncondens'ed vapors the desired distillateproduct'pass out: ofithecolumn through the line 75'to. a condenser 76 ofany suitable type.

The condensed products discharged through the line 72 into the-tower 73are subjected to the stripping action. of steam therein. A

" pool of such product's is collected in the lower portion ofthe tower 73, as at77' and steam is introduced .thereinto'through the line 78.

The steam and vapors-stripped: from the,

portion ofjthe column 60, suitably above the I line 7-2.- :TheE.stripped condensate, :which forms the composite feedstock tothe heatingcoil, is withdrawn. through, line 8 1 and forced by pump 82 through li e83'to the line 42.

I-nthe'operation "t the. modified form. of construction as shown in Fig;2,- the composite feed to the heating coils, derived as-hereim after setforth, isfsupplied through the-line 42 to theinitial heating. section43, wherein, it is brought to an elevated temperature be low itsvaporizing and crack-ing temperature'. It then; .passes-through the line44 tothe vaporizing and cracking section "of the-furnace, "45, whereinit is subjected to rapid heating to completely vaporize. it, rapidlybringing it to the 1desi red cracking'temperature toefiect the desiredamount of cracking. In heating the oil in the pipe still 40,'the

same principles are employed as in the pipestill 7 in connection withthe'first form of apparatus illustrated. However, in the modified formof apparatus, since 'a' part the desired cracking is effected in thereaction chamber 47," less cracking pass is. necessary in the pipestill, .the' through-pubis cor respondingly increased and thetemperature gradient in the coil therefore'varies somewhat.

from that \x 'hich'is obtaitied when the entire cracking, desired issecured in the heating coil. .'This is illustratedby the broken linegraph -II in Fig; '5, which represents a suitable temperature gradientsecured in the pipe Still of thelay-ou-t of Fig. 2,;which is similar tothat of Fig. 1, but with the. routing ofthe 'oil modified sothatitpasses. downwardlysuceessively'through the top .eleven rows, then is.

carried down to the bottom row and-risesupf wardly through the remainingsevenrows- By this routing, it will be seen'from the graph that thefoil'is graduallybrought to 1 a. temperature below 700? F.-, at'whichappreciable cracking begins." .It' is brought from this temperature to ahigh cracking temperature of about 860 in traveling through two rows oftubes, wherebythe low temperaturecracking of the'liquid oil isminimized, and the oil is subsequently brought to .an outlet temperatureof. about 925 before entering" the reac' .t.ion chamber 47.

The vaporized products are then discharged through the line 46 into thevertical reaction chamberAT -through the distributor 48 in th lowerportion thereof, this distributor-having an outwardly flared opening ashereinbfore described, so as to reduce the velocity of the flow of thevaporized material and prevent turbulence in the reaction chamber. Ingeneral, no appreciable quantity of tarry liquid is present. The level,when present, is held low, and the discharge opening 48 of the preheater outlet pipe 46 is preferably disposed a slight distance above thelimit of level of liquid. when present.

The vapors ascend slowly and without substantial turbulence through thereaction chamber to the vapor outlet 51. The lack of substantialturbulence is indicated by the temperature gradient in the reactionchamber, which should be a minimum of 10 to 15 F., with 5% or more ofcracking to gasoline (based on the composite feed to thecoil) takingplace in the reaction chamber. -Thus, in a typical operation, with 175to 180 lbs. pressure in the reaction chamber, the outlet temperature ofthe heating coil about 925 F., the total cracking per pass based on thecomposite feed from 20 to 22%, of which approximately half is effectedin the reaction chamber, a temperature gradient of about 30? has beensecured in the vapors in the drum, the temperature of the vapor near thedischarge" opening 49 being about 890 and that of the vapor near theoutlet 51 being about 860 F. Such a temperature .gradient indicateslittle or substantially no turbulence I in the vapors in the reactionchamber and an appreciable stratification thereof, a slow, even progresstoward the vapor outlet and optimum conditions for vapor phase crackmg.

modified form of apparatus illustrated in 5 5% per pass is tent in thecoils 67 and 68 chamber through theiline 51 and tarry liquid,

if any, from the lower portion thereof through the line 54, ash'ereinbefore sta'ted. Part of the fresh feed supplied to the system,which may have been preheated to some exin the fractionating column 60,may be, passed through the helical coil 55 which surrounds the taroutlot 54 in the reaction chamber 47 and is then dischargedt-hroughoutlet 53 directly into the body'of vapors therein. It mixes with theoutgoing cracked vapors and enters the lower The general conditions ofoperation in the i i g; The St am portion of the fractionating column 60together with the tarry liquid from the reaction chamber. The pressureon the cracked vapors may be substantially reduced on passing throughvalve 61, preferably to' a value of from 10 to 60 lbs. gauge.

The vapors of the cracked products, which include the desired distillateproducts and heavier constituents, together with the vapors of the feedstock introduced into the reaction chamber separate from liquid in thelower portion of the column 60, entrained liquid being separated fromthe vapors by the action of the plates (55. The vapors rise through thevapor conduit 64 in the draw-off plate 63 and enter the upper portion ofthe fractionating column, in which the heavier constituents of thevapors are condensed. The lighter constituents,

istillate products, pass out through the line 75 to any suitablecondenser or fractional condensing device 76.

The condensate formed in the upperportion of the column, which includesthe vaporized constituents derived from the cracking operation heavierthan the desired gasoline product as well as the constituents of thefeed stock, collects in the draw-elf plate 63, passes out through theline 72 and enters the stripping tower 73, descending downwardly through fractionating plates 79 countercurrent to stripping steamand'vapors. A

pool of the composite liquid, which forms the feed for theheating coilsand reaction chamber, collects in the lower portion of the strippingtower,'and steam from the line 78 is passed into it to'eliect thedesired stripand vapors from the stripping operation pass through theline 80 into the lower portion of the column 60. The stripped compositefeed is withdrawn from the stripping tower 73 through the line 81 by thehot oil pump '82 and discharged through line 83 into the inlet line 42of the heating coil 41. 0 In carrying out the operation, the conditionswith reference to temperature, pressure and cracking to gasoline perpass (based on a total composite feed) are substantially similar tothose maintained in operating in the type of lay-out illustrated inFig. 1. That is,

the pressure in the reaction chamber 47 is maintained between 100 lbs.and 406 lbs., the temperature at theoutlet of the 001i and in thereaction chamber being from 825 to 9759' F., and the minimum amount ofcracking to gasoline per pass within this range of temperatures andpressures "arying from about 13% per pass at 250 lbs. to about 2.5% perpass at 100 lbs. for a product having 1.5 cc. tetraethyl leadequivalent. Of this cracking, from one-fourth to three-fourths maybeeffected in theheating coil 41 and the remainderin the reaction chamber47, being ordinarily about equally divided between the two. It is thusapparent that by operating stripping tower 73 reaches the with 'a'layoutas illustrated in Fig. 2, with a coil of a given size, amuch greaterdistillate productioncan be secured than with the form of apparatusillustrated in Fig. 1.

The following specific example illustrates the operation .oftheflayoutsuch as that of Fig. 2 in accordance with the present invention.

The composite feed drawn from the V A heating .coil 41 at a temperature.of about550 and a pressuresufiicient to give a-coiloutlet pressure and apressure in the reaction chamber" of 175 to 180 lbs. In passingjthroughthe coil,

the oil is heated to about 925F. and is then discharged into thereaction chamber, the operationofwhich has been hereinbe'fore described.In the reaction'chamber,a teinpen ature gradient of-from-'8 90 'F. toabout860 F. is maintained and the rate of flow of the oil is socontrolled that a total crackingto gasoline of to 22%] per pa'sson'thertotal composite feed passing through the coil is secured,approximately halfof this'be-in secured intheheating coil. Thefreshfeed;

which; amounts to about one-fourth of the r are cooled to about 325 F.before leaving to enter the condenser.

The liquid-products, securedin such an op.

eration are, based on thefreshffeed, from 69 to 70% of 'a gasoline-motorfuel having an anti-knock valueequiva-lent to 2 cubic centimetersioftetrwethyl lead per. gallon of Mid- Continent gasoline,'.andabout 20% of'an 8 A. PQI. gra-vit-y'tarry liquid.

Within the range of [temperatures and pressures herein set forthforoperation in accordance with th present invention,decreasein-pressure, increase in temperature or increase inpercentage ofcracking. to gaso line per pass tend to increasethe value'vof the fuel.product. *Thus, at-'1QO -lbs. pressure, and about 0 F. coil outlettemperature',' in an operation without the reaction chamber, wi th -.about 29% cracking per pass,a product -havingia 2.0 cc. lead equiva;-.lent is secured, and by raising the proportion of cracking to gasolineperpass to about 26%, aproduct having a; leadequ-ivalent of about 2.5secured. The total yield-of gasoline is, however, somewhat decreasedt-hecapacity ofthe unit-is correspondingly decreased. In; a similaro oration2117 250 lbs. pressure, 875 'F., and al? per pass, a product of about1.5 cc. lead equivalentis obtained; at 925 F. outlet temper ature andthesame pressure, with about 26.5% cracking to gasoline perpass-,aprodraising the per cent of as hereinbefore described, in whichthe vapors anti-knock.

out 25% cracking to gasoline.

uct of2.0cc. lead equivalentis secured; and' at the latter temperatureand pressure, on

per passto about 33%,a product of 2.5 cc.

lead equivalent is secured;

Certainoffthe features. of apparatus and operation hereinset forth areseparately de-v scribed and claimed in the application of Snow, SerialNo.j428,430, filed February 14, 1930; Snow, Serial No. 428,431, YfiljedFebruary 14,. 19:30, and Snow, filed April 25,1930.

Althoughthe invention has been set forth in connection withvariousspecific details of.

apparatus and] of operation, and is especially adapted for operation inconnection there-- with, it is not intended that these shall; beregarded as limitations upon-the scope of the invention, except in sofar as included in the accompanying claims.

-We claim:

1. The method of producing alow boiling motor fuelproduct havinganti-knock char;--

ac-teristics. which comprises rapidly heating a higher boilingsubstantially completely vaporizable hydrocarbon oil from ate'mperaturebelow a substantial cracking temperature to vaporize it and bringthevapors to a cracking temperature between about 850 and about 975 111,holdingtheoil vapors at a tempera- -t ure betweenabout' 850 and about975 while maintaining thereon apressure from about lbs. toabout 400 lbs,for a period of time sufiicient to secure'aiminimum pro-.-portionperpass of desired characteristics ranging-from about 2.5% at 100lbsrto about13% at 400lbs.:of

. the totalmaterial treated, said rapid heating of the oil beingaccomplished at such a rate thatat least 85% of. the said totalconversion per pass is effected at the said temperatures.

bet-ween about850 and about 97 5 F., thereby securing a gasoline motorfuelproduct having an-anti-knock equivalentbf atleast. 1.5 cc. oftetraethyl lead per ,gallonjof Mid-Confi nent gasoline. 2. ThemethodofprOducinga'Iow boiling: motor fuel product having anti-knockchar-1acteristics whichjcomprisesrapidly heating a higher boilingsubstantially completely vaporizable hydrocarbon-oil. from a temperaturebelow a substantial cracking temperature to vaporize it and bring thevapors'to a crack ing temperature between about- 850 and about 975F.,;holding the oil vaporsat' a temperature between about: 850 and about 975F..- while. maintaining thereon a' pressure from about-100 lbs. to about250 lbs. for

a periodfof time sufiicient to secure. a mini-V mumproport on per pass.of cracked prodnot of the desired; characteristicsiranging from about2.5%.at 100' lbs. to about 13% at 250--lbs. of the total materialtreated,- said rapid heating of the oil, being accomplished at Such arate that at least 85% of the said cracking 'to gasoline Serial. No.447,265,

crackedproduct of the ,tial cracking temperature least 85% totalconversion per pass is effected at the said temperatures between about850 and about 975 F., thereby securing a gasoline motor fuel producthaving an anti-knock equivalent ofat least 1.5 cc. of tetraethyl leadper gallon of Mid-Continent gasoline.

3. The method of producing a low boiling motor fuel product havinganti-knock characteristics which comprises rapidly heating a higherboiling substantially completely vaporizable hydrocarbon oil, comprisinga mixture of fresh charging stock and recycle stock, from a temperaturebelow a substanto vaporize it and bring the vapors to a crackingtemperature between about 850 and about 975 F. while maintaining thereona pressure from about 100 lbs. to about 400 lbs. for a period of timesuflicient to secure a minimum proportion per pass of cracked product ofthe desired characteristics ranging from about 2.5% at 100 lbs. to about13% at 400 lbs. of the total material treated, said rapid heating of theoil being accomplished at such a rate that at of the said totalconversion per pass is eflected at said temperatures between about 850F.and about 975 F., fractionating the cracked vapor products as refluxcondensate undesired higher boil-- ing constituents thereof, separatelycollecting the desired fractionated ing said reflux condensate withfresh oil and subjecting the said mixture to the aforesaid crackingoperation.

4. The method of producing a low boiling motor fuel product havingantiknock characteristics which comprises'forcing a higher boilingsubstantially completely vaporizable hydrocarbon distillate 'oil in arestricted stream through a heating coil, applying heat thereto a arapid rate to raise the oil from a temperature below a substantialcracking temperature and'to rapidly vaporize the oil and bring thevapors to a cracking temperature between about 850 and about 975 F., andmaintaining the vapors at a temperature between about 850. and about 975F. and at a .per pass is effected at the said pressure of from about 100lbs. to about 400 lbs. for a period of time sufficient to secure aproportion of cracked products of the desired characteristics based uponthe total material treated in a minimum proportion per pass varying fromabout 2.5% at 100 lbs. to about 13% at 400 lbs, said rapid heating ofthe oil being accomplished at such a rate that at least of the saidtotal conversion temperatures between 850 and 975 F.

5. The method of producing a low boiling motor fuel product acteristicswhich comprises forcing a higher boiling substantially completelyvaporizable hydrocarbon distillate oil in a restricted stream through aheating coil,-applying heat thereto at a rapid rate to raise the oil frm toseparate vapors, and admix' having anti-knock cha r-- a temperaturebelow a substantial cracking temperature and to rapidly vaporize the oiland bring the vapors to a cracking temperature between about 850 andabout 975'F., and maintaining the vapors at a temperature between about850 and about 975 F. and at a pressure of from about lbs. to about 400vaporizable distillate oil to raise the oil from a temperature below asubstantial cracking temperature to rapidly and completel y vaporize theoil and bring the vapors to a temperatureof about 900 F., maintainingthe vapors at a temperature above 850 F. but not above about 900 F. andapressure of about to lbs. to convert at least 20% thereof into thedesired said conversion operation being so controlled that atleast 85%of the total conversion of the oil into desired motor fuel product iseffected attemperatures above 850 F., thereby securing a motor fuelproduct having an anti-knock equivalent of at least 2 cc. tetraethyllead per gallon ofMid-Continent gasoline.

7. The method of producing a low boiling motor fuel product havnganti-knock char-- acteristics which comprises passing 'a higher boilingsubstantially completely vaporizable hydrocarbon oil through a heatingcoil while maintaining at the outlet thereof a pressure of from about100 to-about 400 lbs, rapidly heating the oil in its flow through thecoil to vaporize theoil and raise it from a temperature below atemperature of 700 F. and bring the vapors to a cracking temperature ofat not substantially above least 850 F. and 975 F., maintaining thevapors at said cracking temperature above 850 F. and not 'above- 975 F.to secure a totalcrack'ed product in the gasoline range of boilingpoints per pass in a minimum amount ranging from about 2.5% at 100 lbs.to about' 13% at 400 lbs. of the total material treated, said conversionoperation being so controlled that at least 85% of the total con-versionper pass is' effected at temperatures of at least 850 F., whereby aproduct having high anti-knock properties is' produced. 1

8. The method of producing a low boiling motor fuel product havinganti-knock characteristics which comprises passing a higher motor fuelproduct, i

during its passage a substantial cracking temperature to rapidly motorfuel product having distillate 011 through a heating coil whilemaintaining an outlet pressure on said coil of from about 100 to about{100 lbs, heating it therethrough from below vaporize the oil and bringthe vapors to a cracking temperature above about 850 F. and notsubstantially above about 975 F., continuing the heating of the oilwhile in flow throughsa-id coil to maintain the oil at a temperaturebetween about 850 F. and about 975F. and tosecure a'total amount perpass of the desiredrracked product in the gasoline range of boilingpoints in a minimum-amount ranging from about at 100 lbs. to about 13%at 400 lbs. of thetotal material treated, said heating'of thc oil beingso controlled that-.more than 85% of the desired amount of crackedproduct in. the gasoline range of boiling points is formed while the oilis at temperatures above about 850 F.,thereby producing a motor fuelproduct in the gasoline range of boiling points havinga high antiknockvalue.

9. The method of. producing a low boiling anti-knock characteristicswhich comprises flowing a higher boiling substantially completelyvaporizable distillate oil through a. coil,.main taining a pressure onthe outlet thereof of from about 100 to about 400 lbs., heating the saidoil in its'flmv-through the-coil from below a substantial crackingtemperature td rapidly and completely vaporize the oil and bring thevapors to a cracking temperature above 850 'F. but not above 975F.,passing the heated vapors into an enlarged chamber and causing themto travel slowly therethrough while maintaining therein a pressureapproximating the outlet pressure on the coil and a terns perature-above850F. but-not above 975 F., andretaining the vapors inthe coil and theenlarged chamber at saidcracking temperature for a suflicient period oftime torsecure a conversion thereof into motor fuel products in thegasoline boiling point range in a mini mumamount per pass" ranging fromabout 2.5%' at 100 lbs. pressure to about 13% at 400 lbs, the heatingofthe oil in said coil being accomplished atsuch a rate that less than 15%of thetotal conversion per pass is effected at temr'i'eraturesbelow 850F., whereby a motor fuel product in the gasoline boiling point.

range having av high anti-knock value "is secured. i

' 10.. The method of producing a'low boiling motor 'fuel product havinganti-knock characteristics which comprises flowing a higher boilingsubstantially ,completely' vaporizable' distillate oil through a coil,maintaining a pressure on the outlet thereof from about 100 to about 400lbs, heating the said oil in its flow through the coil from below asubstantial cracking temperature to rapidly and completelyvapo'rize theoil and bring the vapors to'a cracking temperature above 850 F. butnotabove 975 F.,-passing the heated vapors into 'an .enlargedfsubstantiallyunobstructed chamber and causing them to travelslowlyand quietlytherethrough while per-' mitting Stratificationof the vapors,maintaining within the chamber a pressure approximating the outletpressure on the coil and' a temperature above 850 F. but not/above 975F.,- and retaining the vapors in the coil and the enlarged chamber atsaid cracking-temperature for a sufiicient period of time to secure aconversion-thereof into motor fuel products in the gasoline boilingpoint range in a minimumamount per pass rangingfrom about 2.5% at 100lbs. pressure to about 13% at 400 lbs., the heating of the oil in saidcoilbeing accomplished at such a rate that less than 15% of the' totalconversion per pass is effected at temperatures below, 850" F., wherebyamotor fuel'product in the gasoline boiling point range having a highanti-knock value is secured;

11.' The method of producing a low boiling motor fuel product havinganti-knock characteristics which comprises passing a higher boilingsubstantially completely vaporizable distillate oil through a coil whilemaintaining an outlet pressure thereon of about 100 lbs. to about 400lbs., heating the. oil inits flow through the coil from below asubstantial cracking temperature to rapidly bring it to crackingtemperature and to rapidly and completely vaporize the oil and heat thevapors to'a cracking temperature above about 850 F. but not above about975. F., then passing the vapors into an enlarged chamber and causingthem'to pass slowly therethrough while-maintaining therein a pressure offrom 100 lbs,to- 400 lbs; and a temperature above about 850 F. but notsubstantially above about 975 F., saidvapors' being maintained at acracking temperature above 850 F. but not suhstant1ally'above-975 F.-inthecoil .and enlarged chamber for a sufficient period to convert intomotor'fuel products in the gasoline boiling range a desired portionthereof in a minimum amount per pass ranging from about 2;5'%'at 1 0t)lbs. pressure to about 13% at 400'lbs., the Qapor's being main-- tainedin the'enlar'ged chamber a sufiicienf' period to effect from aboutone-fourth to about three-fourths of said cracking therein, the saidheating of the oil in said coil from below a-cra'cking temperature to. atemperature above about 850 F.-being conducted at such ratethatsubstantially less than 15% of the total motor fuel productsformed-in the coil and enlarged chamber are produced at temperaturesbelow 850 F.

12. The method of producing a low boiling motor fuel'product havinganti-knock 'char-. acteristics whichcomprises forcing a substan' tiallycompletely vaporizable distillate bydrocarbon oil heavier than gasolinethrough a coil,heating the oil in its passage through the coil frombelow a substantial cracking temperature to rapidly and completelyvaporproduct having an anti-knock value of about 2 cc. tetraethyl leadper gallon, the said heating of the oil in said coil being so controlledthatthe oil is brought from below cracking temperature to a temperatureof about 850 F. while efl'ecting less than 15% of the total conversionper pass into the desired anti knock motor fuel product.

13. The methodof producing a low boiling motor fuel product havinganti-knock characteristics which comprises forcing a substantiallycompletely vaporizable distillate hydrocarbon oil heavier than gasolinethrough a coil maintained under an outlet pressure of about 17 5 to 180lbs., heating the oil in its flow through the coil from below asubstantial cracking temperature to rapidly and completely vaporize theoil and bring the vapors to a cracking temperature above 850 continuingthe heating of the oilvapors to secure a coil outlet temperature ofabout- 925 F., the oil vapors being maintained at'a cracking temperatureexceeding 850 F. but not above 925 F. to secure a conversion thereofinto gasoline-like products of about 15% 'per pass, the said heating *ofthe oil in said coil being so controlled that the oil' i brought frombelow cracking temperature to a temperature of about.850 F. whileeffecting less than :15

passinto-th'e desired motor fuel product. 1 L The 'method ofproducing alow boiling 'motorffiuelprodu'ct having anti-knock characteristics"which comprises passing a higher boiling substantially completelyvaporizable distillate oil through a coil maintainedunder an outletpressure of. about 175 to 180 lbs.

.heating the oil in passage through the coil from below a substantialcracking temperature to rapidly and completely vaporizethe oil and bringthe oil vapors to a cracking temperature above 850'F., continuing theheat ing of the oil in its flow through the coil to secure an outlettemperature thereofofabout 4 925 F., discharging the oil vapors into an.

enlarged chamber, said chamber being largely filled with vapors, causingthe vapors to pass slowly through said chamber without turbulence and ata temperature exceeding 850 F. but not above 925 F., the oil vaporsbeing maintained at cracking temperature above 850 F. for a periodsufficient to seof the total-conversion per I gasoline motor fuel curea. total conversion thereof into gasolinelike products of'about 15%, thesaid heating of the oil in said coil from below a cracking temperatureto atemperature above 850 F. being conducted at such a rate-that lessthan 15% of the total motor fuel products formed in the coil andenlarged'ehamb'er are produced at temperatures below 850 F therebyforming hydrocarbons in'the gasoline range of .boiling points having ahigh anti-knock value. I

. 15. The method ofproducing a low boiling motor fuel product'havinganti-knock characteristics which comprises rapidly heating a higherboiling substantially completel-y vaporizable hydrocarbon oil from atemperature below a substantial cracking temperature to vaporize it andbring the vapors to a cracking temperature between about 850 and about975 F., holding the oil vapors at a temperature between about 850 andabout .975 F. while maintainingthereon.a 'prcs sure from about 100'lbs.to about/00 lbs. for i a period of time sufficient to secure a minimumproportion per pass of cracked prodnot of the desired characteristicsranging from about 2.5% at 100 lbs. to about 13% at400lbs. of the totalmaterial treated, said rapid heating of the oil being accomplished in arestricted'passage located in a radiant heating zone and at such a ratethat at least of the said total conversion per pass' is effected at thesaid temperatures between about 850 and about 975 F., thereby securingagasoline motor fuel product having an anti-knock equivalent of at least1.5 cc. of tetraethyl lead per gallon of Mid-Continent gasoline. v

16. The method of producing a low boiling motor fuel product havinganti-knock characteristics which comprises rapidly heating a higherboiling substantially completely vaporizable hydrocarbon oil from atempera-' tnre below a substantial cracking tempera turc to vaporize itand bring the vapors to'a cracking temperature between about 850 andabout 975 F., holding the oil vapors ata temperature between about 850and about 975 F. while maintaining thereon a pressure from about 100lbs. to about 250 lbs. for a period of time sufficient to secure aminimum proportion per pass of cracked product of the desiredcharacteristics ranging from .about 2.5% at 100 lbs. to about 13% at 250lbs. of the total material treated, said rapid heating of the oil'beingaccomplished ina restricted. passage located in a radiant heating zoneand at such-a rate that at least 85% of the said total conversion perpass is effected at the said temperatures between about 1 850 and about975 F thereby securing a product having an. antiknock equivalent of atleast 1.5 cc. of tetra- 'lethyl'lead per gallon of Mid-Continent gasome. a

. 17. The method of producing allow boiling idly bring the vapors to acracking tempera,-

ture of about 850 F.-, continuing the heating of said vapors 'to'bringthem'to, a temperature of from about875 to about 950 F.,

and holding the oil vapors at atemp'erature between about 875 andabout-95? F. "while conversion per pass I motorfuel productris' effectedwhile the maintainin thereon a pressure of from about 1 00 l s.'toabout.250 lbs.- to secure a minimum conversion fthereof into gasolinelikeproducts of about 20% per pass,the.

said rapid heating of theoil being so controlled that at least 85% ofthe total into 7 the oil is at a temperature above about 850? Ftherebysecuring a; gasoline motor fuel prod]- uct having ananti-knockequiyalent of at least -1.5 cc. of" t'etraethyl lead-pergallon of Mid-(lontinentgasoline.-

' HAROLD .R.SNOW.

FREDERICK W. S LLIVAN, J

desired.

izs

